The functional development of the brain is being investigated in the neonatal rat receiving periodic exposures to low concentrations of lead. The effect of lead on behavioral and biochemical development in various brain regions is under investigation. Our previous behavioral studies showed that the 1- to 10-day old neonatal rat is uniquely sensitive to brain damage by lead. The objective of this research is to determine the relationship between dose and age and functional and biochemical changes induced by lead in different brain regions. The study will use neonatal rats and include blood and brain lead concentrations found in children exposed to lead with and without acute toxic signs.